Method for utilizing temperature to determine a battery state

A method for determining a battery state, comprising:

• charging the battery;
• discharging the battery through a load at a substantial rate for a period of time;
• measuring a battery voltage before ending the discharge;
• measuring a battery temperature before ending the discharge;
• comparing the voltage measurement to a voltage setpoint adjusted according to the measured temperature;
• determining the battery state based on the comparison;
• monitoring battery voltage during discharge;
• interrupting the discharge by removing the load when the monitored voltage reaches a desired voltage level;
• measuring unloaded battery voltage;
• and
• (a) if the unloaded voltage is greater than the desired voltage, discharging the battery for a period of time by reconnecting the load, and then continuing the method at the previous step (measuring unloaded battery voltage);
• (b) if the unloaded voltage is equal to or less than the desired voltage, interrupting the discharge.

A method for evaluating a state of a battery having a solid state memory device, the method comprising:

• charging the battery for a period of time;
• (a) measuring a battery voltage before ending the charging;
• (b) measuring a battery voltage upon or after the charging;
• discharging the battery through a load at a substantial rate for a period of time;
• (c) measuring a battery voltage before ending the discharging;
• measuring a battery temperature before ending the discharging;
• comparing the difference between the voltages measured in steps (a) and (c) to a first setpoint adjusted according to the measured temperature;
• comparing the difference between the voltages measured in steps (b) and (c) to a second setpoint adjusted according to the measured temperature;
• and
• evaluating the state of the battery based on the comparisons to the first and second setpoints.